The present invention relates to a mechanism to be used in connection with a sample vessel in which a target substance is exposed to one or more agents in order to determine the time resolved interaction between the target substance and agent(s). More particularly the present invention relates to such a mechanism having an oscillatory movement for oscillating a sample holder within the sample vessel without changing volume of the sample vessel. Even more particularly, the present invention relates to such a mechanism in which a finger-like member, formed by a welded steel bellows, projects into the sample vessel and is attachable to the sample holder and in which the oscillatory movement acts upon the welded steel bellows and therefore the sample holder.
Detailed knowledge of the time resolved interaction between substances is important in determining the most proper and efficient industrial utilization of such substances. For instance, a complete understanding of the preferential adsorption characteristics of an adsorbent (a target substance) is critical for the practical utilization of the adsorbent in an industrial process involving the adsorption of a multicomponent, e.g. a binary mixture (containing two different agents) to be adsorbed by the adsorbent.
In case of adsorbents, the adsorption characteristics of an adsorbent may be determined through Fourier transform infrared techniques. The theory behind such methodology is that an adsorbent has active adsorbent centers that are infrared sensitive so that a spectrum can be determined that indicates the adsorption interaction with such active sites. The intensity of specfic bands of the spectrum is concentration dependent and thus, after calibration, one can quantitatively find the amount of the component that has ben adsorbed by the adsorbent. Measuring the amount of component within the adsorbent is a time dependent function. As a result, until equilibrium has been reached, the kinetics of adsorption of the adsorbent can be followed.
The disadvantage of Fourier transform infrared techniques is that they are only applicable to adsorbents that interact with adsorbates in an infrared sensitive spectra. Also, Fourier transform infrared techniques are only applicable at very high concentration steps. Thus, there exists classes of adsorbate/adsorbent interactions that cannot be followed through conventional techniques such as Fourier transform infrared techniques as well as interactions between adsorbates and adsorbents at very low concentration gradients.
Another method is to place the adsorbent into an sample vessel and to expose the adsorbent to agents capable of being adsorbed by the adsorbent. At the same time accurate pressure and composition measurements within the sample vessel have to be carried out. Advantages of such method include the lack of a requirement for interactions to be evidenced by infrared spectra and that the method is applicable at very low concentration steps. The technique involved in carrying out the method is discussed in Fundamentals of Adsorption, Proc. IVth Int. Conf. on Fundamentals of Adsorption, Kyoto, May 17-22, 1992, Hille et al., pp. 285-292 (1993). The problem with the technique is that, during its performance, a boundary layer can be rich in the agents interacting with the adsorbent forms which introduces errors into the measurements to be taken within the sample vessel.
As will be discussed, the present invention overcomes the difficulty involved in carrying out the aforementioned method by providing a movement for oscillating the sample holder to disrupt the boundary layer without changing volume of the sample vessel.